How to Test a Coolant Temperature Sensor
- Step 1 - Locate Coolant Temperature Sensor. The coolant temperature sensor is located on the engine block under the hood.
- Step 2 - Connect Digital Volt-Ohm Meter. Testing the coolant temperature sensor is a very quick process. With the use of...
- Step 3 - Check Readings. For the testing process you will need to turn the engine on.
Full Answer
How to tell if coolant temp sensor is bad?
Symptoms of a Bad Coolant Temp Sensor
- Check Engine Light. The dashboard check engine light is a warning sign that your CTS may be bad. ...
- Poor Mileage. The fuel efficiency of your engine depends on the level of heat it is producing. ...
- Electrical Cooling Fans not coming on. ...
- Black Smoke from the Exhaust Pipe. ...
- Difficult Starting Condition. ...
- Engine Overheating. ...
- Poor Idling. ...
- Poor Engine performance. ...
What are the symptoms of a bad coolant temperature sensor?
Symptoms of a Bad or Failing Coolant Temperature
- Engine Light Checking. An indication of a possible issue with the coolant temperature sensor is the illumination of the Check Engine Light on the dashboard.
- Hard Start at Certain Temperatures. ...
- Engine Overheating. ...
- Poor Fuel Economy. ...
Where do I find the coolant temperature sensor?
Part 2 of 3: Remove and replace the coolant temperature sensor
- Make sure vehicle is on a level working area. ...
- Locate the coolant temperature sensor. The first item that needs to be completed after you compiled all of your tools and assets is to locate the coolant temperature ...
- Jack the front end for clearance. ...
- Remove radiator cap and overflow cap. ...
- Drain the radiator. ...
- Replace drain plug. ...
Where is coolant temp sensor and what's it do?
On most vehicles, the coolant temperature sensor (CTS) can be found somewhere near the engine thermostat, which allows it to function optimally. The tip of the CTS is probably located right next to the engine coolant. The sensor works by measuring the temperature that's being given off by the thermostat and/or the coolant itself .
What is the correct way to check a coolant temperature sensor?
Submerge the sensor in the water and take a reading. Wait a minute or so for the screen to give you a reading of the cold water. Once you have a reading, write down the measurement for reference. A common reading for a temperature sensor in cold water is around 5 volts.
How do you test if a temperature sensor is working?
How to test a faulty thermocouple or resistance thermometer?Check if the -ve and +ve leads swapped.Check for any thermocouple cable wiring issues.Check for local heat source issues.Check Temperature Transmitter Settings.Check temperature controller settings.Troubleshooting temperature sensors with a multimeter.More items...
How do you know if you have a faulty coolant sensor?
The main symptoms of a bad or failing coolant temperature sensor include:Check Engine Light.Poor Mileage.Electrical Cooling Fans not coming on.Black Smoke from the Exhaust Pipe.Hard Start Condition.Engine Overheats.Poor Idling.Poor Engine performance.
How many ohms should a coolant temperature sensor have?
Coolant temp sensors have a very steep temp vs resistance curve. 25K ohm or so is normal for perhaps 30F ambient temperature. It drops very rapidly with heating, until at normal engine temperature, the reading is between 600 and 1000 ohms.
How do I test a sensor with a multimeter?
Multimeter Test: VoltageReconnect the sensor's power source.Disconnect the power wires at the sensor (Point C in the diagram) or connection point closest to the sensor (Point B, if the cable to your sensor cannot be disconnected at the sensor).Maintain the same probe – multimeter connections.More items...•
Can you bypass a temperature sensor?
You can bypass it with a regular resistor, but you have to know the value associated with the thermister. To find the value: -Disconnect the thermister, and apply a meter to it and read initial resistance value.
What happens when a coolant temperature sensor goes bad?
The coolant temperature sensor can fail and transmit cold signals to the computer. This action confuses the computer and stimulates it to enrich the fuel mixture unnecessarily. This can cause the fuel mixture to be vibrant such that during combustion, the fuel can't be adequately consumed within the chamber.
Is there a fuse for coolant temperature sensor?
There isn't one per se. There will be a fused wire with voltage to the instrument cluster (your owners manual should indicate which fuse), but the temperature sensor is providing a variable "resistance to ground," which the temperature gauge in the dash is reflecting.
Does the coolant temp sensor control the thermostat?
The sensor works by measuring the temperature that's being given off by the thermostat and/or the coolant itself. The temperature is then sent to the on-board control system.
How do you test a single wire coolant temperature sensor?
1:2910:15How to Test a Coolant Temperature Sensor - YouTubeYouTubeStart of suggested clipEnd of suggested clipAnd things like that so what I have here at this page is a printout of the engine coolantMoreAnd things like that so what I have here at this page is a printout of the engine coolant temperature sensor resistance.
How do you test a sensor resistance?
To test for resistance, set the DVOM to Ohms scale. Unplug the sensor and connect either leads to the DVOM probes. Read the Ohm or resistance values and compare them to those of the manufacturer. If they don't match, the sensor is defective.
How do I check my temperature sending unit?
1:253:06Troubleshooting Oil Pressure and Water Temperature GaugesYouTubeStart of suggested clipEnd of suggested clipCold. If you remove the sending unit wire. But the gauge still reads hot you may have a shorten theMoreCold. If you remove the sending unit wire. But the gauge still reads hot you may have a shorten the wire or a faulty age. You can test this by removing the sender wire from the back of the gauge.
How do you test a 3 wire temperature sensor?
0:081:39How to test your RTD with a Meter - YouTubeYouTubeStart of suggested clipEnd of suggested clipIn order to do this we're gonna need our multimeter our mini hook test leads one PR 11 100 ohm threeMoreIn order to do this we're gonna need our multimeter our mini hook test leads one PR 11 100 ohm three wire RTD. And one RTD 833 wire RTD the first thing I'm going to do is I'm going to take my meter.
How do you test a single wire coolant temperature sensor?
1:2910:15How to Test a Coolant Temperature Sensor - YouTubeYouTubeStart of suggested clipEnd of suggested clipAnd things like that so what I have here at this page is a printout of the engine coolantMoreAnd things like that so what I have here at this page is a printout of the engine coolant temperature sensor resistance.
How do you test a temperature sending unit?
1:253:06Troubleshooting Oil Pressure and Water Temperature GaugesYouTubeStart of suggested clipEnd of suggested clipYou can test this by removing the sender wire from the back of the gauge. And running a jumper wireMoreYou can test this by removing the sender wire from the back of the gauge. And running a jumper wire from the gauge connection to ground.
How does a single wire temperature sensor work?
0:3015:43Introduction to 1-Wire Temperature Sensors - YouTubeYouTubeStart of suggested clipEnd of suggested clipThat's a digital chip it converts the temperature. And then communicates back to a one wire master.MoreThat's a digital chip it converts the temperature. And then communicates back to a one wire master. Using ones and zeros essentially. It communicates on a one-way or bus.
Step 1 - Locate Coolant Temperature Sensor
The coolant temperature sensor is located on the engine block under the hood. Pull the latch for the hood and open it, making sure it is secure bef...
Step 2 - Connect Digital Volt-Ohm Meter
Testing the coolant temperature sensor is a very quick process. With the use of a digital volt-ohm meter you can easily tell if the sensor is fault...
Step 3 - Check Readings
For the testing process you will need to turn the engine on. Let the engine run for a full two minutes to allow the engine to get up to running tem...
Step 4 - Check With Cold Sensor
If you have a new sensor on hand and want to check it, you can do this easy test. Connect the black lead of the meter to the body of the cold senso...
Step 5 - Replace Defective Coolant Temperature Sensor
Replacing the coolant temperature sensor is an easy process that anyone can do at home with some basic mechanic's tools. Remove the lead coming fro...
How to check coolant temperature on a car?
1. Unplug the sensor electrical connector. 2. Get the engine surface temperature using an infrared thermometer or suitable cooking thermometer. Take the engine temperature on a location near the coolant temperature sensor. Before going on to the next step, let's divert here for a second:
Where is the coolant sensor located?
However, one of the most common locations is on or near the thermostat housing .
What happens if the ECT sensor doesn't change?
If the ECT sensor's resistance didn't change as the engine temperature rose, replace the sensor. If your sensor only registers infinite resistance, the sensor has a broken internal contact and you need to replace it. If the sensor only registers zero resistance, the internal contacts are shorted. Replace the sensor.
How does a bad coolant sensor affect engine performance?
A bad engine coolant temperature sensor affects engine performance: It may cause a constant lean air/fuel mixture, causing the engine to stall or idle rough. Or it may cause a constant rich air/fuel mixture, causing an increase in emissions and fuel consumption.
Can you test an ECT sensor with water?
On the next video, you'll see an alternative method to test a sensor using water. Of course you need to remove the sensor from the vehicle to use this method. However, the video will give you a visual reference about how to test your ECT sensor. Check it out.
Can a bad ECT sensor cause engine problems?
On modern vehicles, a bad ECT sensor will upset ignition timing. On some vehicle models, a bad ECT sensor may upset the transmission, cooling fan, and temperature gauge as well. But before you blame the coolant temperature sensor for your engine problems, though, use this guide to test the sensor to confirm that you actually need to replace it. ...
What to do if coolant sensor isn't working?
If you suspect the sensor isn’t working properly, you can test a coolant temperature sensor or simply replace it. It’s one of the few parts in your car that’s cheap enough that it’s often easier to just replace it rather than spend time testing it.
How many wires does a temperature sensor have?
In many case you may find two sensors; one for the computer and a second one for the temperature gauge. The sensor for the computer will have at least two wires, while the sensor for the gauge often has just one wire.
How to test a temperature sensor?
Steps for testing the sensor 1 Depending on the model of your vehicle, a poor temperature sensor can cause the failure of the cooling fan, the transmission as well as the temperature gauge. 2 It interferes with the ignition timing 3 It is prone to causing constant fuel mixture hence causing damage to your engine and also excessive consumption of fuel.
Where is the temperature sensor located?
For you to locate the temperature sensor, you have to open your vehicle. Most of the temperature sensors are usually located close to the thermostat housing. However, depending on the model of your car, you might also find the temperature sensor attached to a cylinder head.
How does a bad temperature sensor affect the engine?
Some of the most common methods include; Depending on the model of your vehicle, a poor temperature sensor can cause the failure of the cooling fan, the transmission as well as the temperature gauge.
What happens if the temperature sensor does not change?
If the temperature sensor does not change with the rise in engine temperature. If one or more wires are damaged, you also need to fix them to have your temperature sensor working effectively. If the internal temperature sensor has a damaged internal contact, it needs to be replaced.
What temperature should coolant be before dropping?
Additionally, make sure your engine reaches the operating temperature of about 200F (93) before dropping.
How to tell if coolant temperature sensor is bad?
If your vehicle starts to use a lot more gasoline than usual, or black smoke is starting to come from the exhaust pipe, these are indicators that the coolant temperature sensor in your vehicle could be defective, and needs to be replaced.
Why is my coolant temperature sensor not working?
Another telltale sign of your coolant temperature sensor not functioning properly is if your engine is overheating frequently . This can possibly happen when the coolant is leaking, causing the temperature sensor to behave erratically .
What causes a check engine light on a car?
In many vehicles, a faulty coolant temperature system will trigger a check engine light or service engine light on your car's dashboard. A quick trip to a qualified mechanic with a diagnostic computer will tell you if the check engine light has anything to do with a coolant temperature sensor or not. Interested in Leasing?
How many temperature sensors are there in a vehicle?
There may be two temperature sensors in some vehicles, one to send information from the engine system to the control unit and another from the control unit to the dashboard. However, some vehicles dispense with the need for two temperature sensors by using just one sensor to do both tasks.
Is a coolant sensor a thermistor?
Thus, principally, the coolant temperature sensor is a thermistor. The temperature of a thermistor influences its resistance in an inverse proportion. As the temperature rises, the resistance of the car's coolant drops and this in turn decreases the potential difference output.
How to check a coolant sensor?
How to Diagnose a Faulty Engine Coolant Temperature Sensor? 1 Connect an OBD2 Scanner and look for related trouble codes. Check the live data to see the temperature from the sensor. If it is way off the range, check the wirings, and replace the sensor. 2 Locate the coolant temperature sensor in your vehicle by referring to the service manual. 3 Find the coolant temperature sensor and remove the connector plugs. 4 If you have two pins on the coolant temperature sensor, you can try ohm measure between these two pins. 5 Check your repair manual for the correct ohm-value at a given temperature. 6 If the value is wrong – replace the sensor. 7 If it seems fine, check the wirings and connectors between the coolant temperature sensor and the engine control module.
Where is the coolant temperature sensor located?
The engine coolant temperature sensor is usually located on the engine block or cylinder head. It is often installed on a plastic hose on the coolant’s inlet. Different brands and car manufacturers have different ways of placing the coolant temperature sensor depending on the car design. Some vehicles may have more than one temperature sensor, ...
What does a faulty ECT sensor do?
A faulty ECT sensor can send a false signal to the onboard computer, resulting in an incorrect air-fuel mixture. For example, a faulty sensor can send a signal indicating the engine is cold when it is not, and more fuel will heat the engine quickly.
Why won't my electric cooling fan come on?
Electrical Cooling Fans not coming on. Some cars use the engine coolant temperature sensor to control the electric cooling fans. You have two separate temperature sensors for the fans, dashboard gauge, and engine management in most cars. However, if your car has a single sensor, a bad engine coolant temperature sensor may result in your fans won’t ...
How much does it cost to replace a coolant temperature sensor?
The average coolant temperature sensor replacement cost is between $50 to $250, depending on the car model and labor costs. A coolant temperature sensor costs 30$ to 100$, and the labor costs 20$ to 150$.
What does it mean when a car lights up with a check engine light?
If the computer detects any problem with the sensor’s circuit, it will illuminate the check engine light, indicating that the car needs an inspection. If you see a check engine light on your dashboard, it is time to check the trouble codes with an OBD2 scanner.
What causes an engine to overheat?
Engine Overheats. The cooling fan, which is behind the radiator grille, removes heat from the engine’s coolant. This fan is electrically controlled and relies on the signal from the onboard computer. If the fan receives a false signal, the fan might not turn on, causing the engine to overheat. Some vehicles have a separate coolant temperature ...
Where is the coolant temperature sensor located?
In most cars, the primary ECT sensor (ECT sensor 1) is installed near the thermostat in the cylinder head or block or on the thermostat housing. A second coolant temperature sensor could be installed in another part of the engine, or in the radiator.
How much does it cost to replace an engine temperature sensor?
In some cars, a special deep socket might be required. Replacing the engine temperature sensor in a repair shop costs from $59 to $129 (labor) for an average car.
What is a CHT sensor?
The CHT sensor (see the photo) works the same way, but it measures the temperature of the cylinder head metal and is not immersed in coolant. This allows the CHT sensor to measure the temperature of the engine correctly even with loss of coolant. This can help prevent overheating. An ECT sensor is connected to the main computer (powertrain control ...
How to test ECT sensor?
Testing the ECT/CHT sensor Resistance: One way is to measure the resistance of the sensor at different engine temperatures and compare the readings to the specifications listed in the service manual. Measuring the resistance ...
Can you measure resistance of a sensor?
The resistance of the sensor can only be measured when the sensor is disconnected from the circuit. The reason is that if you measure the resistance of any electrical component that is still connected to the circuit, the measurement won't be accurate. The resistance was 2,953 Ohm when the engine was cold.
What happens if you have a temperature controller with a B sensor?
For example, if you have your temperature controller setup for Type S input but attach a Type B thermocouple sensor it would display an incorrect temperature and lead you to believe your sensor was faulty. You will need to make sure the input selected on the controller matches the type of thermocouple or resistance thermometer connected to it.
How to test a faulty thermocouple?
Testing a faulty thermocouple with a multimeter. Get your faulty thermocouple and a multimeter. Change your multimeter to Continuity beeper/diode symbol/flow of current. Some multimeters will beep if there is a break in the circuit, some multimeters will beep when the circuit is complete.
Why is my thermocouple reading high?
If your thermocouple is reading high, it could be because your sensor is located too close to a heat source. If your sensor is near a local heat source it could increase the temperature being measured as opposed to the position you wish to measure temperature.
What is Peak Sensor?
Peak Sensors are experts in temperature sensors and a short cut to solving your temperature problems is to contact us . We can help solve your sensor problems and either repair or manufacture replacement sensors.
Can you check if a thermocouple is short?
One check you can carry out with a thermocouple is if you short the +ve and -ve wires in a terminal connection head, if the instrument and any compensating cables are setup correctly the instrument will give an ambient reading.
Can a thermocouple be wired incorrectly?
Incorrect wiring of thermocouple cables can be further complicated because thermocouples often use compensating cable. It is possible that the compensating cable is incorrectly wired to the thermocouple. It may appear correctly wired at the instrument but not correct between the thermocouple and compensating cable. To avoid this, make sure -ve and +ve legs match correctly along the full length of the thermocouple, to the compensating cable, to the instrument.
